The present invention concerns human growth hormone (hGH) containing pharmaceutical compositions. More precisely, it concerns compositions of saccharose-stabilized human growth hormone. It is known that the highly purified proteins are time-unstable and are stabilized, for instance, in admixture with saccharides, such as lactose and mannitol, or else with proteins and aminoacids, such albumin and glycin.
Human growth hormone is secreted in the human pituitary. In its mature form it consists of 191 amino acids, has a molecular weight of 22,000 and thus is more than three times as large as insulin. This hormone is a linear polypeptide containing two intrachain disulfide bridges. Until the advent of recombinant DNA technology, hGH could be obtained only by laborious extraction from a limited source: the pituitary glands of human cadavers. The consequent scarcity of substance limited its application to treatment of hypopituitary dwarfism even though it has been proposed to be effective in the treatment of burns, wound healing, dystrophy, bone knitting, diffuse gastric bleeding and pseudarthrosis. HGH can be produced in a recombinant host cell, in quantities which would be adequate to treat hypopituitary dwarfism and the other conditions for which it is effective.
The major biological effect of hGH is to promote growth. The organ systems affected include the skeleton, connective tissue, muscles and viscera such as liver, intestine and kidneys. Growth hormone exerts its action through interaction with specific receptors on cell membranes.
Compositions of lyophilised proteins are described in M. J. Pikal, Biopharm, October 1990, 25-30. There are reported examples of growth hormone formulations with stabilizing excipients such as mannitol, glycin, arginine and lactose.
In particular, the lyophilisation is described in the presence of various substances in their amorphous state, as sugars, which increase the collapse temperature and permit to obtain shorter lyophilisation times. However, it is not feasible, according to the author, to foresee a standard formulation for all the proteins, and the choice of the best formulation requires a remarkable selection work.
German patent DE 3520228 describes bioactive proteins, including growth hormone, in formulations which are stabilized by means of polysaccarides comprising repetitive maltotriose units.
WO 89/09614 describes formulations of human growth hormone stabilized with glycine, mannitol and a buffer, wherein the molar ratio of human growth hormone:glycine is 1:50-200.
U.S. Pat. No. 5,122,367 patent describes a controlled release system for administration of growth hormones, which comprises the protein and a polysaccaride incorporated within a polymeric matrix.
EP 210039 patent application describes a controlled release implant for subcutaneous administration to an animal of bovine or porcine growth hormone, in the form of a matrix containing 40% saccharose.
According to the present invention, hGH may be either natural or synthetic, i.e. produced on the basis of recombinant DNA technology, the latter being preferred.
The injectable formulations of human growth hormone are obtained by a process which includes their lyophilisation in order to obtain a dry powder. Human growth hormone is highly liable to denaturization during the lyophilisation process and it desirable to obtain stable formulations to maintain a longer cycle life when they are stored at room temperature.
In order that materials like hGH be provided to health care personnel and patients, these materials must be prepared as pharmaceutical compositions. Such compositions must maintain activity for appropriate periods of time, must be acceptable in their own right to easy and rapid administration to humans, and must be readily manufacturable. In many cases, pharmaceutical formulations are provided in frozen or in lyophilized form. In this case, the composition must be thawed or reconstituted prior to use. The frozen or lyophilized form is often used to maintain biochemical integrity and the bioactivity of the medicinal agent contained in the compositions under a wide variety of storage conditions, as it is recognized by those skilled in the art that lyophilized preparations often maintain activity better than their liquid counterparts. Such lyophilized preparations are reconstituted prior to use by the addition of suitable pharmaceutically acceptable diluent(s), such as sterile water for injection or sterile physiological saline solution, and the like.
Alternatively,the composition can be provided in liquid form appropriate for immediate use. Desirable is a liquid formulation which maintains its activity in long term storage.
Current formulation of hGH lose activity due to formation of dimer and higher order aggregates (macro range) during formulation processing as well as during storage and reconstitution. Other chemical changes, such as deamidation and oxidation may also occur upon storage.
Human growth hormone is found on the market in formulations stabilized for example with mannitol (Saizen.RTM. and Grorm.RTM. Serono).